Calculating Water Output of a 2.0 hp Electric Motor

In summary, the 2.0 hp electric motor pumps water from 10 m below the surface using 745.8 Joules per second. In one hour or 3600 seconds, it will pump a total of mgh = 9381 Joules of energy. The volume of water being pumped does not matter in this energy problem, but for reference, 1000 liters of water is equal to 1000 kg or 1 cubic meter. The equation used to calculate the energy is Power = Energy/Time, where Energy = mgh.
  • #1
psingh
18
0
A 2.0 hp electric motor on a water well pumps water from 10 m below the surface. The density of water is 1.0 kg per liter. How many liters of water does the motor pump in 1 hr?

im not sure what equation to use on this problem, so if anyone could let me know that would be good thanks!
 
Physics news on Phys.org
  • #2
Power = Energy/Time

Energy = mgh in this case

1 hp = 745.8 Watts
 
  • #3
A motor is working on increasing the potential energy of water (calculated by PE = mgh) by bringing it up the well 10 meters below. The motor is using 745.8 Joules per second (745.8 Watts). In one hour or 3600 seconds, how many kilograms of water will it be pumping up?

Does that make the question easier?
 
  • #4
yea i understand the question a tiny bit more, but don't you have to find the volume of water being pumped up?

this is what i got so far but I am completely not sure since its 2 hp..

745.8w*2*3600s= is the energy of the motor in 1 hour.
h= -10 or 10 depending on where u place your axis
g= 9381

745.8w*2*3600=mgh? is that right?
 
  • #5
g = 9.79 meters per second per second

And hint about volume. The volume doesn't matter in this energy problem. Just know for later reference that 1000 liters of water = 1000 kg = 1 cubic meter.
 
  • #6
oo thanks a lot i got it now =]
 
  • #7
mezarashi said:
g = 9.79 meters per second per second

Not 9.81? Where do you live?

And hint about volume. The volume doesn't matter in this energy problem. Just know for later reference that 1000 liters of water = 1000 kg = 1 cubic meter.

Well, volume does matter because the problem asked for volume!
I presume you meant that since, for water, 1 litre is 1 kg, it's easy to convert.
 

1. How do you determine the water output of a 2.0 hp electric motor?

The water output of a 2.0 hp electric motor can be calculated by multiplying the motor's horsepower by the constant 1.36. This will give you the motor's output in gallons per minute (gpm). For example, a 2.0 hp electric motor would have a water output of 2.72 gpm (2.0 hp x 1.36 = 2.72 gpm).

2. What is the formula for calculating the water output of an electric motor in hp?

The formula for calculating the water output of an electric motor in horsepower (hp) is: hp = (gpm x psi) / 1714. This formula takes into account the motor's gallons per minute (gpm) and the pressure (psi) it is operating at, and divides it by the constant 1714.

3. Can the water output of a 2.0 hp electric motor be increased?

Yes, the water output of a 2.0 hp electric motor can be increased by either increasing the motor's horsepower or by increasing the pressure at which it operates. However, it is important to note that increasing the pressure beyond the motor's recommended limit can cause damage to the motor and should be done with caution.

4. How does the size of the impeller affect the water output of an electric motor?

The size of the impeller does not directly affect the water output of an electric motor. However, the size and design of the impeller can impact the motor's efficiency and ultimately affect its water output. A larger or more efficient impeller can increase the motor's output, while a smaller or less efficient impeller can decrease the output.

5. Are there any factors that can affect the accuracy of calculating the water output of an electric motor?

Yes, there are a few factors that can affect the accuracy of calculating the water output of an electric motor. These include variations in pressure and flow rate, as well as the efficiency and condition of the motor itself. It is important to regularly maintain and calibrate the motor to ensure accurate calculations of its water output.

Similar threads

  • Introductory Physics Homework Help
Replies
9
Views
878
  • Introductory Physics Homework Help
Replies
3
Views
2K
  • Introductory Physics Homework Help
Replies
2
Views
2K
  • Introductory Physics Homework Help
Replies
7
Views
1K
Replies
5
Views
1K
Replies
1
Views
1K
  • Mechanical Engineering
Replies
15
Views
804
  • Introductory Physics Homework Help
Replies
3
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
4
Views
1K
Back
Top